Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-01-09
Astronomy and Astrophysics
Astrophysics
13 pages, LaTeX, Submitted to ApJ
Scientific paper
10.1086/307590
An unsolved problem in turbulent dynamo theory is the ``back reaction'' problem: to what degree does the mean magnetic field suppress the turbulent dynamo coefficients which are needed to drive its growth? The answer will ultimately derive from a combination of numerical and analytical studies. Here we show that analytic approaches to the dynamo and back reaction problems require one to separate turbulent quantities into two components: those influenced by the mean field (which are therefore anisotropic) and those independent of the mean field (and are therefore isotropic), no matter how weak the mean field is. Upon revising the standard formalism to meet this requirement, we find that: (1) The two types of components often appear in the same equation, so that standard treatments, which do not distinguish between them, are ambiguous. (2) The usual first-order smoothing approximation that is necessary to make progress in the standard treatment is unnecessary when the distinction is made. (3) In contrast to previous suggestions, the correction to the dynamo $\a$ coefficient found by Pouquet et al (1976) is actually independent of the mean field, and therefore cannot be interpreted as a quenching.
Blackman Eric G.
Field George B.
No associations
LandOfFree
Resolution of an ambiguity in dynamo theory and its consequences for back reaction studies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Resolution of an ambiguity in dynamo theory and its consequences for back reaction studies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Resolution of an ambiguity in dynamo theory and its consequences for back reaction studies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-391058